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Journal Articles

Characterization of liquid targets in Vacuum condition

Yamamoto, Kazami; Ogiwara, Norio*; Kuramochi, Masaya*

e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.359 - 364, 2023/07

https://doi.org/10.1380/ejssnt.2023-053

In recent years, durable target is required according to increase of the beam power. To solve this problem, a liquid film was formed in vacuum and tested it as a target. An ethanol and a mercury were selected as liquid target materials, and we investigated whether the liquid sheet could be formed stably in a vacuum and how about the vacuum pressure. As a result, it was confirmed that the liquid films were stably formed in both case and the pressures with the films were about the vapor pressure of the materials.

Journal Articles

Dependence of charge-exchange efficiency on cooling water temperature of a beam transport line

Yamamoto, Kazami; Hatakeyama, Shuichiro; Saha, P. K.; Moriya, Katsuhiro; Okabe, Kota; Yoshimoto, Masahiro; Nakanoya, Takamitsu; Fujirai, Kosuke; Yamazaki, Yoshio; Suganuma, Kazuaki

EPJ Techniques and Instrumentation (Internet), 8(1), p.9_1 - 9_9, 2021/07

https://doi.org/10.1140/epjti/s40485-021-00067-6

The 3 GeV Rapid Cycling Synchrotron at the Japan Proton Accelerator Research Complex supplies a high-intensity proton beam for neutron experiments. Various parameters are monitored to achieve a stable operation, and it was found that the oscillations of the charge-exchange efficiency and cooling water temperature were synchronized. We evaluated the orbit fluctuations at the injection point using a beam current of the injection dump, which is proportional to the number of particles that miss the foil and fail in the charge exchange, and profile of the injection beam. The total width of the fluctuations was approximately 0.072 mm. This value is negligible from the user operation viewpoint as our existing beam position monitors cannot detect such a small signal deviation. This displacement corresponds to a 1.6310 $^{-5}$ variation in the dipole magnetic field. Conversely, the magnetic field variation in the L3BT dipole magnet, which was estimated by the temperature change directly, is 4.0810 $^{-5}$ . This result suggested that the change in the cooling water temperature is one of the major causes of the efficiency fluctuation.

Journal Articles

Production and compilation of charge changing cross sections of ion-atom and ion-molecule collisions

Imai, Makoto*; Shirai, Toshizo*; Saito, Manabu*; Haruyama, Yoichi*; Ito, Akio*; Imanishi, Nobutsugu*; Fukuzawa, Fumio*; Kubo, Hirotaka

Journal of Plasma and Fusion Research SERIES, Vol.7, p.323 - 326, 2006/00

no abstracts in English

Journal Articles

Formation of a charge-exchange target for fast ions in the plasma of large-scale toroidal devices under NBI conditions

Mironov, M. I.*; Khudoleev, A. V.*; Kusama, Yoshinori

Plasma Physics Reports, 30(2), p.164 - 168, 2004/02

https://doi.org/10.1134/1.1648943

Times Cited Count：0 Percentile：0.02(Physics, Fluids & Plasmas)

High-energy charge-exchange diagnostics can determine the distribution function of fast atoms produced via the neutralization of hydrogen ions by hydrogen-like impurity ions. Deriving the distribution function requires to know the composition and spatial distribution of the target ions in a plasma. A charge-exchange target forms as a result of the interaction between impurity nuclei and beam atoms. Depending on the arrangement of heating beams with respect to the diagnostics, it is necessary to calculate their trajectories. A model which takes into account elementary processes resulting in the ionization equilibrium of the ions of impurities in a specific tokamak configuration is proposed. The model is applied to the JT-60U plasma. Mechanisms for the formation of charge-exchange atomic flows are considered. The relative contributions of different heating injectors to the charge-exchange flow are estimated. Based on the calculated results, a method is proposed for local measurements of the ion distribution function with a stationary analyzer.

Journal Articles

Asymmetry of dense divertor plasmas influenced by thermoelectric potential and charge-exchange momentum loss

Hayashi, Nobuhiko; Takizuka, Tomonori; Hosokawa, Masanari*; Shimizu, Katsuhiro

Journal of Nuclear Materials, 313-316(1-3), p.1041 - 1045, 2003/03

https://doi.org/10.1016/S0022-3115(02)01534-9

Times Cited Count：3 Percentile：25.75(Materials Science, Multidisciplinary)

Asymmetric equilibria of divertor plasmas influenced by the thermoelectric potential and the momentum loss due to the charge-exchange have been studied by using the five-point model. The momentum loss becomes large when the divertor plasma temperature decreases below about 10 eV. The pre-sheath potential is increased by the momentum loss and compensates for the decrease in the thermoelectric potential at the low-temperature side of the asymmetric equilibrium. Through The change of the pre-sheath potential, the momentum loss has a stabilizing effect on the thermoelectric instability and mitigates the asymmetry. To lower the temperature by the recycling at the one-side divertor, the high recycling and the resultant momentum loss at the other-side divertor are effective because of the bifurcated structure of the equilibrium.

Journal Articles